1. Field of the Disclosure
The present disclosure relates to a display device, and more particularly, to a display device capable of preventing luminance variance and preventing increased power consumption caused by its large size.
2. Related Art
Recently, a variety of flat panel displays capable of overcoming shortcomings of considerable weight and volume of a cathode ray tube (CRT) have been developed. Example of flat panel displays include a liquid crystal display (LCD), a plasma display panel (PDP), an organic light emitting diode (OLED) display, etc.
The OLED display is a self-emitting display which electrically excites an organic compound so as to emit light. The OLED display can be implemented in a compact structure that simplifies its manufacturing process since it does not require a backlight. In addition, the OLED display has advantages of a low-temperature manufacturing process, a high response speed of less than 1 ms, low power consumption, a wide viewing angle, a high contrast, etc.
The OLED display includes an emission layer formed of an organic material between an anode and a cathode. The emission layer emits light by energy generated when excitons, which are hole-electron pairs generated from recombination of holes supplied from the anode and electrons supplied from the cathodes in the emission layer, are dropped to the ground state.
Referring to FIG. 1, illustrated is a cross-sectional view of a conventional OLED display 10. The conventional OLED display 10 includes a thin film transistor TFT and a capacitor Cst formed on a substrate 12, an insulating layer insulating the thin film transistor TFT, the capacitor Cst and a common power line 14, and a first electrode 18 formed on the insulating layer 16 and coupled to the thin film transistor TFT. In addition, the OLED display 10 includes a bank layer 20 formed on the first electrode 18, an organic emission layer 22 formed on a portion of the first electrode 18, exposed by the bank layer 20, and a second electrode 24 formed on the organic emission layer 22.
The OLED display 10 further includes an auxiliary metal layer 28 formed on and attached to a counter substrate 26 to reduce the resistance of the common power line 14. The two substrates 12 and 26 are effectively bonded to each other using a sealant 32. Here, the auxiliary metal layer 28 and the common power line 14 are not directly connected, but are instead electrically coupled to each other through an Ag dot 30.
There have been several issues with the conventional OLED display 10 of FIG. 1. First, the process of forming an auxiliary metal layer 28 that is attached to the upper substrate 26 reduces production yield. Second, an alignment process for forming the Ag dot 30 to connect the auxiliary metal layer 28 and the common power line 14 to each other requires high accuracy and may cause poor contact between the common power line 14 and the auxiliary metal layer 28.